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Archive for February, 2020

Day 194: Know your spinal cord – The spinoreticular tract

vertebrae of the spine

vertebrae of the spine

We’ve arrived at day thirty-seven in the spinal cord series and we’re still covering new ground. You can find all of our sweet spinal cord action in the neuroanatomy category, which at this point is pretty extensive for a high-level look. Yesterday we talked about the reticulospinal tracts so today we are talking about the sister tract, the spinoreticular tract. Are they related, or is it all just in the name?

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Day 193: Know your spinal cord – The reticulospinal tracts

reconstruction of the nuclear masses of the brain stem
reconstruction of the nuclear masses of the brain stem

Reconstruction of the nuclear masses of the brain stem

It’s day thirty-six in our spinal cord series and I yesterday I lied, we’re not done quite yet. First, as always we have a super helpful neuroanatomy category for anyone wanting to read the posts from this series. For the rest of us, today we’re talking about the reticulospinal tracts, yes tracts with an s. There is a good reason for this, but you’ll have to read on to see why. (more…)


Day 192: Know your spinal cord – The Tectospinal tract

Cervical spinal cord cross-section

Cervical spinal cord cross-section

Welcome to day thirty-five in the know your spinal cord series! For the new people, we have a whole neuroanatomy category dedicated to these posts! For everyone else (or those of you just interested in today’s topic, this is going to be on another smaller tract of the spinal cord we haven’t covered yet. Today we are talking about the tectospinal tract, not to be confused with the spinotectal tract, so let’s get started.

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Day 191: Know your spinal cord – The Vestibulospinal tract

cranial nerves
cranial nerves

No, we’re not moving away from the spine, but we are talking about the cranial nerves.

It’s day thirty-four in our spinal cord series. As usual, if you’re new here welcome and you can find each and every post in our series in the handy neuroanatomy category! All the posts are in reverse chronological order and while we don’t technically have a specific order, you should probably start with the medullary pyramids and work your way forward. If you’re here, then you probably are interested in the vestibulospinal tract, something we haven’t covered yet, but fear not, we are going to do that now.

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Day 190: Know your spinal cord – The landmarks

human cervical spinal cord cross section
human cervical spinal cord cross section

A human cervical spinal cord slice. Once you’ve read this post, you should be able to identify the major parts and tell which side is the front of the cord.

Welcome to day thirty-three in our series. For those of you who are just finding us, we have every one of these posts in our neuroanatomy category in reverse chronological order. Today we’re going to backtract (get it?) a little and go over something basic, but something we’ve skipped over to this point. We never really talked about the landmarks of a spinal cord slice. So today, we are going to take a detour and go over spinal cord features.

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Day 189: Know your spinal cord – The Ramus

dorsal rami innervation

Today is day thirty-two in our know your spinal cord series. If you’re just joining in, as I usually do in the intro, we have a whole neuroanatomy category just for these posts so you don’t have to dig for them! Today we are covering a couple of structures that fall under the same broad category, ramus. What are they and what do they have to do with the spinal cord? Well that’s what we’re about to find out!

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Day 188: Know your spinal cord – The spinal nerves (revisited)

spinal roots

spinal roots

Here we are at day thirty one of knowing your spinal cord and we’re still going strong. I’m very happy that I cataloged all of these posts in the super handy neuroanatomy category, which should make it easy for you to find each and every one of them! Today we’re talking about something we’ve touched on in the past, but deserves its own post, the spinal nerves. We need to cover this for the next couple of posts, where things get a little… odd. So let’s get started!

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Day 187: Know your spinal cord – The anterior white commissure

Cross section of human spinal cord
Cross section of human spinal cord

Cross section through human spinal cord (lumbar region, L1) showing motor neurons. Astrocytes and oligodendrocytes are labeled ‘A’ and ‘O’, respectively. The objective magnification used is 40x.

Welcome to day thirty of knowing your spinal cord. I feel like that is a lot of spinal cord knowledge for just covering the basics. In any case, if you’re just finding us, welcome! I’ve created a whole new neuroanatomy category just for these posts so you can find them easy and they are in reverse chronological order. Is the anterior white commissure a tract of the spinal cord? Well not really, but it does have an important job and we keep referencing it, so let’s talk about what it does exactly.

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Day 186: Know your spinal cord – The spino-olivary tract

Spinal cord slice
Spinal cord slice

Spinal cord anatomy

Day twenty-nine, wow does time fly! We have over four weeks worth of fun spinal knowledge for you to tap into, all in reverse chronological order in our handy neuroanatomy category! If you read the title, you know we’re back on tract (see what I did there?). Today we’re talking the spino-olivary tract, or is it the olivospinal tract? Keep reading to find out!

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Day 185: Know your spinal cord – Cauda equina syndrome

Cuada equina disection

Here we are on day twenty-eight of knowing your spinal cord. A friendly reminder, the entire series has its own neuroanatomy category where you can catch up on any posts you missed or if you just want a reminder on something we already covered. We’ve already covered quite a bit of spinal disorders, but there is one more that I want to talk about and like our series where we started at the top of the cord and worked our way down, we are now going to cover damage to the bottom of the cord, specifically the cauda equina.

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Day 184: Know your spinal cord – Motor neuron disease

ALS2

Kultschitzky staining was used here and shows marked symmetrical demyelination (whitening regions) in the anteriolateral roots (especially pyramidal tract) of the spinal cord

It’s day twenty-six already! For those of you who are just finding us, you can find all of the posts in our super cool neuroanatomy category. We’ve already covered a lot of spinal disorders, but one of the larger diseases that we have yet to cover is motor neuron disease. Technically a family of diseases, we will look at the commonalities and causes, so with that introduction, let’s get going.

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Day 183: Know your spinal cord – The H-reflex

Diagram showing how we measure the H-reflex
Diagram showing how we measure the H-reflex

We measure the H-reflex by applying an electrical stimulus (S) behind the knee, the ground (G) gets placed around the soleus and the recording electrode (R) is placed inline below, this is the route the nerve takes.

Yesterday we had a bit of a break so I could share a critical review paper. That means this is day twenty-five of the know your spinal cord series! We’ve also hit the halfway mark in our 365 days of academia challenge! If you’re new here, you can find all of the fun spinal cord knowledge we’ve amassed by checking out our neuroanatomy category! We are going to take a step away from spinal cord disorders to talk about something we kind of covered, but deserves a more in-depth exploration. This is all you wanted to know about the H-reflex, so let’s dive in.

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Day 182: Review – Modulation of soleus stretch reflexes during walking in people with chronic incomplete spinal cord injury

Fig2

Figure 2 of the paper showing examples of the soleus H-reflex (labeled H) during standing  and during different phases of walking in a participant without known neurological injuries (top) and in a participant with chronic incomplete SCI (bottom).

Today is my third attempt at a critical review paper. Since my PI gets a copy, so do all of you! You can read my first looking at elbow spinal stretch reflexes here. Or my second where I review modulating spinal cord excitability with a static magnetic field here. Today is an interesting paper on soleus stretch reflex and H-reflex. I really appreciate the methodology the researchers used and they did an excellent job of highlighting the limitations to the study, which is always important. Per the usual disclaimer, this is my third critical review, so you can take my opinion n the methodology and findings how you will. (more…)


Day 181: Know your spinal cord – Tabes dorsalis

vintage anatomy

We’ve made it to day twenty-four of fun spinal cord knowledge! If you’re just joining us, we have a whole new neuroanatomy category for you to find all the posts in this series in reverse chronological order. If you want to know everything, then you’ll want to start at the beginning with the medullary pyramids. Over the past week in our series we’ve been talking about spinal cord disorders and today we are looking at something called tabes dorsalis, let’s begin!

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Day 180: Know your spinal cord – Lichtheim’s disease

Nitrous-Oxide-Induced-Subacute-Combined-Degeneration

MRI showing Lichtheim’s disease caused from nitrous oxide (we show another case below)

It’s day twenty-three in our little series called know your spinal cord. For those just finding us, you can read the rest of the posts in our special neuroanatomy category created just for these posts! If I’ve counted correctly, this will be the seventh post on different spinal cord disorders and today we are covering something called Lichtheim’s disease, so let’s take a look.

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Day 179: Know your spinal cord – Central cord syndrome

Transverse human spinal cord slice stained

Transverse human spinal cord slice stained

Welcome to day twenty two in the knowing your spinal cord series! As per my usual intro, you can find the rest of the series in reverse chronological order under our spiffy new neuroanatomy category. Today we are covering another type of spinal cord injury, like the last two posts, this will cover what happens when a certain area (central area) of the cord is damaged. With that, let’s talk spinal cord.

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Day 178: Know your spinal cord – Anterior spinal artery syndrome

Spinal_cord_histology

Today we hit the three week mark in knowing your spinal cord! I’m hoping we can do a full four weeks, that would be quite the collection of knowledge. For those of you just joining in, you can find all of our posts in the neuroanatomy category ordered in reverse chronological order.  As per the last few posts, we’ve covered the majority of the anatomy and now we are looking at different disorders of the spinal cord. Today we’re going to cover another type of injury, this one called anterior spinal artery syndrome, so let’s get started!

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Day 177: Know your spinal cord – Brown-Sequard Syndrome

vintage spinal cord anatomy art

We’ve made it to day twenty in our little series on knowing your spinal cord. As always, you can find each and every post in this series through our neuroanatomy category. Since we’ve covered all the major neuroanatomy, the latest posts have been on spinal cord diseases and disorders. That said, today we’re covering Brown-Sequard syndrome, so let’s take a look at what this is.

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Day 176: Know your spinal cord – Spina bifida

spinal dissection

This is day nineteen of knowing your spinal cord! We covered all the big neuroanatomy and while we may go back and cover some of the minor things, we’re in the middle of spinal deformities. For those just starting, we have a neuroanatomy category to make it easy to find these posts. For everyone else, today we’re talking about spina bifida.

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Day 175: Know your spinal cord – Diastematomyelia

diastematomyelia drawing

Diastematomyelia, a complicated name for a split spinal cord.

Day eighteen! Almost three weeks worth of fun spinal knowledge. For those tuning in, we have a neuroanatomy category just for these posts. Since we’ve covered most of the anatomy portion of the spinal cord, we’ve just started covering spinal disorders. If you’re here you’re probably wondering what diastematomyelia is, so let’s get started!

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Day 174: Know your spinal cord – The tethered spinal cord

brain and spinal cord

This has been a fun series of posts and today is day seventeen! As usual, you can check out all of our posts under the neuroanatomy category. I’ve got some good news and some bad news. The good news is we’re still going! The bad news is we’ve pretty much covered the anatomy. So for the next few posts, we will look at some issues the spinal cord may have. First up, let’s talk about a tethered spinal cord!

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Day 173: Know your spinal cord – The meninges

cross section of spinal cord

Day sixteen of knowing your spinal cord! So many posts, much knowledge! For those who are just finding us, we have a whole neuroanatomy category dedicated to these posts. If you want to take it from the top (literally) you should start with the medullary pyramids post. If you’ve been following along or only interested in this particular topic today we are covering the meninges and you’ll learn my really dumb way for remembering them, so let’s get started.

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Day 172: Know your spinal cord – The lumbar cistern and cerebrospinal fluid

Spinal anatomy

We are well on our way to finishing up the know your spinal cord series that I am doing. Today is day fifteen and as usual if you’re just tuning in we have a whole neuroanatomy category dedicated to these posts for you to check out organized in reverse chronological order. If you want to start at the beginning, that would be the medullary pyramids. Today we are at the other end of the cord, this is the lumbar cistern!

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Day 171: Know your spinal cord – The cauda equina

spinal cord and brain

Here we are at day fourteen of knowing your spinal cord. By now you’re all experts on the spinal cord and I’m not even sure what I’m doing here. For those just joining us, we have a neuroanatomy category with all the posts so you don’t have to dig for them. If you want to start at the beginning, that would be the medullary pyramids. For the rest of you this is the end, not the end of the posts because we have a lot more to cover, but the end of the spinal cord. Let’s talk the cauda equina!

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Day 170: Know your spinal cord – The spinal cord enlargements

Mitochondria in a spinal cord section

Mitochondria in a section of spinal cord

Here we are at day thirteen of knowing your spinal cord! As always, we have a whole special category for these posts called neuroanatomy and if you’re not after a specific topic, I recommend starting at the medullary pyramids. Today’s post is about something important that we haven’t touched on very much, the cervical and lumbar enlargements of the spinal cord, so let’s get started.

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Day 169: Know your spinal cord – The central pattern generator

V0008396 Brain and spinal cord: dissection, back view. Coloured line

Day (or really post) twelve on knowing your spinal cord. We have a whole category for the posts, neuroanatomy. Today we are going to talk about the curious case of the central pattern generators (CPG’s). Unfortunately, we cannot talk about them without talking about the experiments that found them, meaning we will be covering animal studies. In particular, some animal studies that might not sit well with some people. I attempted to be general where I can, just know that it is coming.

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Day 168: Review – Static magnetic field stimulation applied over the cervical spinal cord can decrease corticospinal excitability in finger muscle

Fig1

Figure 1 of the paper showing how the intervention was applied to the spinal cord

As mentioned in yesterday’s post, this is my second critical review paper. You can read my first looking at spinal reflexes here. Today we are looking at a novel way to modulate spinal cord excitability. Overall I find the paper very interesting. Although the authors performed a limited experiment and no follow up (as of now) has been done, it still looks very promising and would provide a new way to explore the circuitry of the spinal cord. This is my second attempt at a “critical review” so you can take my opinion on the methodology and findings how you will.

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Day 167: Know your spinal cord – The reflex pathways

Gold leaf spinal cord art by Greg Dunn design
Gold leaf spinal cord art by Greg Dunn design

Beautiful spinal cord art, used with permission by Greg Dunn design.

Day eleven, we’ve almost spent two weeks covering your spinal cord! Tomorrow we will take a brief break as every two weeks I have a review paper due to my PI in the spinal cord feild, so tomorrow I will share it with all of you as well. For today, remember we have a neuroanatomy category with all of the posts we’ve done. If you’re new I would suggest you start with the medullary pyramids post and work forward, for the rest of you or those of you who are only interested in reflexes, let’s talk about some legos.

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Day 166: Know your spinal cord – The spinocerebellar tract

Spinal cord section by Ramon y Cajal, a Spanish neuroscientist
Spinal cord section by Ramon y Cajal

Drawing of a spinal cord cross section by Ramon y Cajal, a famous Spanish neuroscientist.

Here we are on day ten of knowing your spinal cord. As always, you can find the aggregated posts in my totally new, fresh off the line category, neuroanatomy. There posts are organized in reverse chronological order, so the first post on the medullary pyramids would be at the bottom, which is where I recommend you start if you’re new. For everyone who’s followed along or those of you who are just interested in this one tract, let’s talk about the spinocerebellar tract!

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